Process of extracting metals from their ores.



' W. E. GREEN AWALT. PROCESS OF BXTRAGTING METALS FROM THEIR ORES.APPLICATION FILED MAY 25,1909.

973,776. Patented Oct. 25, 1910.

WI H 3 E a I INVE'NTOR WILLIAM E. GREENAWALT, OF DENVER, COLbRADO.

PROCESS .OF EXTRACTING METALS FROM THEIR ORES.

Specification of Letters Patent.

Patented Oct 25, 1910.

Application filed May 25, 1909 Serial No. 498,328.

To all whom it may concern:

Be it known that I, WILLIAM E. GREENA- WALT, a citizen of the UnitedStates, residing at Denver, in the county of Denver and State ofColorado, have invented certain new and useful Improvements in Processesof Extracting Metals from Their Ores,,of which the following is aspecification.

My invention relates to improvements in processes of extracting metalsfrom their ores.

its application to copper ores, and to ores containing copper withvariable quantities of gold, silver, lead, nickel, cobalt, zinc, andother metals.

Copper ores usually contain variable quantities of other metals, andthese metals cannot be recovered by any oneof the wet methods now inuse. One, and sometimes two, additional treatments are necessary toextract the gold and silver occurring with the copper, and the lead isinvariably lost. One of the essential difliculties with acid processeshas been, that the acid is usually too expensive to admit of extendeduse in mining districts, which are ordinarily loacid precipitant.

of copper from sulfate solutions.

difliculty,

in the past by these methods has been the cated far from thesource' ofacid supply. It takes approximately, 1.5 pounds of sulfuric acid todissolve one pound of copper as sulfate. If hydrochloric acid is used,it takes approximately 0.6 pound of acid to extract one pound of copperas cuprous chlorid, and 1.1'pounds as'cupric chlorid. Much of the acid,whether sulfuric or hydrochloric, combines with the base elements of theore and serves no useful purpose. The amount of acid which it isnecessary to provide, in any rocess, is considerably more than thatcombining with the copper, and all the acid is irrecoverably lost wheniron is used as the Theoretically, 88.8 pounds of precipitate 100 poundsIn ractice, it takes from 200 to 300 poun s of scrap iron. Here,incurred in providing 1ron with which to precipitate the copper. Thefundamental therefore, in treating copper ores iron are required toexcessive cost of the materials.

The essential object of my process is to reduce the costs and make themethod commercially practicable.

In my electrolytic process, herewith dedissolved by' dilute scribed, thecopper is- It will be described more particularly in' agaln, a largeexpense is acid chlorid solutions, and then precipitated byelectrolysis, while at the same time the acid which was combined withthe copper, is multiplied and again regenerated as free acid, at theexpense of sulfur dioxid and water. Salt is the only chemical toprovide, which is not usually contained in the ore. Sulfur dioxid,derived from roasting sulfid ore, is the active chemical consumed.Theoretically, the chlorin in the salt is not consumed, nevertheless, inpractice, about one eighth pound of salt should be provided for everypound of copper produced.

The-oxid, carbonate, and silicate ores of copper may be treated withoutroasting. The sulfids are roasted. If the ore is roasted, salt may beadded during the roasting.

Tn workinr the process, the ore af er being suitably crushed, is placedin large leaching vats for chemical treatment. The first step in thechemical process consists in combining chlorin, generated from metalchlorids by electrolysis, with sulfur dioxid produced by roa -stingconcentrates or sulfid ore, in the presence of water, to form acid. Thismay be shown by the following reactions;-

Both sulfuric acid and cop er sulfatereact with common salt to formhydrochloric acid or cupric chlorid, so that neither the sulfuric acidnor the copper sulfate could exist in the solution. These well knownreactions are Cupric chlorid. when warm and in the presence of othermetal chlorids, acts readily on silver and its compounds in the ore toform silver chlorid, thus c A +ouoi A o1+ouoL form acid, any desiredstrength of acid solution may be obtained forthe copper, and a chlorinsolution-of sufficient strength for the gold.

The cupric chlorid solution issuing from the leaching vat, is saturatedwith sulfur dioxid obtained from roasting sultid ore. This converts thecupric 'chlorid into the cuprous chlorid, thus The object of this is;

First ;-The electric current deposits twice as much copper,theoretically, per ampere, from a cuprous as from a cupric solution, andwith an expenditure of only of the energy per unit of copper.

Second :-The sulfur dioxid, reacting with cupric chlorid and water,produces large quantities of acid. A molecule of acid is in this wayregenerated for every molecule of cupric chlorid reduced to cuprouschlorid. For every pound of copper reduced from the cupric to thecuprous condition, 1.4 pounds of acid is regenerated.

Third ;The excess of sulfur dioxid combines with the chlorin liberatedduring electrolysis of the cuprous chlorid to precipitate the copper,thereby again regenerating 1.4 pounds of acid for every pound of copperreduced from the cuprous condition to metallic copper. The reactions are$8) QCuCl-l-electric current=2Cu+2CL 9 2o1+so,+2H,o=

2HCl+H SO,+75. calories.

These reactions may take place in the electrolyzer. Usually the excessof chlorin will be conducted to a separate chamber where it may combinewith the sulfur dioxid in the solution.

Fourth ;The above reactions give rise to an electromotive force workingwith the current, thereby reducing the necessary volt age in thedeposition of the copper.

Fifth ;It dispenses with the necessity of diaphragms in theelectrolyzers, although at times diaphragms may be desirable.

Sixth ;It is possible by this method, to extract the other valuablemetals. from the ore, with the copper, and with the same solution. Thisis not possible when working on a sulfate basis.

Seventh:Insoluble anodes, decomposing chlorid solutions, are vastly moredurable than when decomposing sulfates. Graphitized carbon electrodeshave proved effective for the decomposition of chlorids, while theproduction of a suitable insoluble anode for the decomposition ofsulfates, may still be regarded as one of the unsolved problems ofelectro-metallurgy.

It is evident, that in depositing one pound of copper, 2.8 pounds ofacid is regenerated at the expense of sulfur dioxid and water. Thisamount of acid is capable of taking up 'mon salt, by electrolysis.

twice the amount of copper fromwhich it was decomposed. The regeneratedacid solution is again applied to the ore, where some of the acid againcombines with the copper, and some with the base elements, principallylime, forming the insoluble calcium sulfate, which remains in the ore. The sulfuric acid is the one which is eliminated by combining with thebase elements, while the hydrochloric acid combines with the copper,again resulting in the formation of the original cupric chlorid. Thiscycle of solution, precipitation, and regeneration, is repeatedindefinitely. When one vat of ore is sufficiently treated the solutionis turned into the next. All the metal chlorids have the faculty ofdisplacing copper from its sulfate combinations. For example, if thereis lime in the ore, as there usually is, both the sulfuric andhydrochloric acids may combine with it. If the hydrochloric acidcombines with the lime, the result will be the formation of calciumchlorid; but the calcium chlorid will at once react wit-h the coppersulfate in the solution and convert it into the cupric chlorid, thus Itis evident, therefore, that the sulfuric acid is the one which iseliminated by reacting with the base elements, and the sulfuric acidresolves itself back to the sulfur dioxid from the roasting furnace. Thebase metal chlorids act as a solvent for the silver chlorid.

If there is gold in the ore, the acid chlorid solution is chargedwith'chlorin, generated, either from the copper chlorid, or from com- Ittakes 1.7 pounds of salt to produce one pound of chlorin, and 5 poundsof chlorin will, ordinarily, extract the gold from a ton of the averagecopper ore. This chlorin is not lost, but is ultimately converted intobase metal 110 chlorid, in which form it is again used to extract thecopper and silver from new charges of ore. Theoretically, none of thechlorin used in the process, whether free or combined, is lost. Itsimply changes its condition from 115 acid chlorid in the" leachingvats, and is again regenerated back to acid by the electrolysis.

It is intended, primarily, to work the process with impure solutions.Any electro- 120 lytic method, depending on pure solutions for success,must of necessity be very unsatisfactory. Nevertheless, in time, thesolution may contain sufficient undesirable elements to make theirremoval advisable. The 125 elements most injurious to copper, arebismuth. arsenic. and antimony. These, together with all the metals ofthe first and second groups may be completely removed from acidsolutions by hydrogen sullid and 130 Should' a more thoroughpurification be de'- sired, the following method is'preferred;

Salt, NaCl, iselectrolyzed to produce chlorin and caustic soda, 'thus-;

current:

Cl-l-NaOH-l-H.

The chlorin so obtained may be used to dis- (12) NaGl +H O+electricsolve the gold if there is any in the ore, or it may beconverted intoacid, thus which is usedto dissolve more copper from the'ore. Thecaustic soda is used to purify the-solution byprecipitating out the baseelements, thus v (14) Ro1 +2Na0H=2Nao1+B (oH) After which the purifiedsolution, regenerated in salt, is filtered from the precipitatedhydroxids.

The acid chlorid solution, as applied to the ore, will issue from theleachin vats bearing the copper as cupric chlorid, although smallquantities of cuprous chlorid may also be present. This solution may" bepassed directly through the electrolytic cells, but it is very muchbetter to first bring itin contact with sulfur diox'id beforeele'ctrolyzing it; Ifa diaphragm is used in the electrolysis of thecuprous chlorid, the solution is first passed through the negativecompartment of the cell where it is freed or partially freed from itscopper, and then passed through the anode compartment in which goldshould there be any in In elcc'trolyzing the cuprous chlorid, it isthesolution is-brought to a higherstate of chlorination and considerablefree chlorin maybe given ofi. This chlorin is conducted to a scrubbingtower, or combining chamber, where it may combine with sulfur-dioxid inthe presence of the solution, e. water) to form acid, or it may beretained in the soluhe ore.

desirable that sulfur dioxid should be present in excess, especiallyifan open cell is used, to prevent ,the liberatedchlorinfromre'converting the cuprous-chlorid into thecupric chlorid. So long asthere: is an excess of sulfur dioxid in thesolution this It is evident,however, that .it

cannot occur.

, is desirable to return the solution to the'ore,

free from sulfur dioxid, and in the highest state of chlorination.

either by a diaphragm cell,or by conducting the free chlorin, liberatedduring electroly-- sis at the anodes,xinto a separate chamber,

Reference is made to This is accomplished convert them into a higherstate of chlorination.

The copper, by this electrolytic method, may be deposited in a granularcondition, and doesnot adhere to'the cathodes. gold and silver occurringin the ore, with the copper, may bedeposited with the'copper,.orseparately,if desired. If the copper needs electrolytic refining, .therewould be no advantage in depositing the metals separately.

The

Havingnowexplained the chemical reactions and general principles of theprocess,I will describe in detail, a practical apparatus for carrying itout.

drawing, in which 1 1s a storage an taming water, or preferably, achlorid solution.

sulfurdioxid pass upwardly, when the reaction, shown by equation (1)takes place.

, The subdividing of the solution greatly fa:

cilitates the reaction." The dilute acid chlofrid solution, issuing fromthe tower, flows into the stora -e and regulating tank 3, from whence itis rawn into the leaching vat as desired. r

4 is a leaching vat, containing theore to 100 be treated. An,agitatorwould do quite as well as the leaching vat, but this point is immaterialin the operation of the process.

. The solution, percolating through the ore,

reacts with-the copper compounds, as shown by equations (2) and (3), andthen issues from the vat l, as a solution of cupric ghlo frld containingalso, perhaps, some cuprous chlorid, and flows into storage andregulating tank 5, from whichit can be passed through the scrubbingtower 6, in an even and continuous stream. The scrubbing tower; orreducing chamber, 6, is constructed similar to the combining tower, 2,and like that, connects with the sulfur dioxid generator, 22. Thesolution, containing the cop d regulating-tank conthe accompanying v I 2is a scgibbing tower, or combining chamber, having-for its object thesubdivlsion of per, mostly as cupric chlorid, dripping down through thereducing tower 6, while in contact wlth sulfur dlOXld, forms a readymeans of. convertingthe cupric chlorid into the. cuprous chlorid,according to the reaction shownby' equation (7).

The partly. regenerated acid cuprous'chld.

rid solution, whichwill also usually contain an excessof sulfur diox d,flows into storage and regulating tank 7 ,from whence it may be.drawn-into the electrolytic copper precipitating cells, 11,. 12, and 13,as desired.

In electrolytically depositing the copper, it

will ordinarily be found most satisfactory to first pass the solutionthrough open cells, that is to say cells without a diaphragm, as

shown by 11 and 12, while maintainlng .an

trolyz'er 11,,where it circulates freely about the cathodes and anodes,the copper being deposited on the cathode, while chlorin is beingliberated at the anodes. Some of this chlorin immediately combines withthe excess of sulfur dioxid, thus regenerating acid, and preventing thecuprous copper from becoming. cupric. The solution, partly deprived ofits copper, and presumably, most of its sulfur dioxid, flows out of the'electrolyzer 11, through pipe 11, into tank 14, from whence it iselevated by means of pump 17 and pipe lines 20 and 20, into tank 8. Itthen again percolates through tower 9, in the presence of sulfur dioxid,so that the solution on flowing into tank 10, and thence intoelectrolyzer 12, again contains sufficient excess of sulfur dioxid tocombine with much of the liberated chlorin and prevent the solution frombecoming cupric. If the solution, issuing from electrolyzer 11 stillcontains a sufiicient excess of sulfur dioxid, it will not be necessaryto pass it through tower 9, but may be flowed by means of pipe 11directly into electrolyzer 12. In the same way the solution, issuingfrom electrolyzer 12, may be passed into'electrolyzer 13, which isrepresented as a diaphragm cell with a closed anode compartment; The.solution for the anode compartment of this cell may be taken directlyfrom electrolyzer 12, or from the cathode compartment of the same cell,but the solution from the cathode compartment, is preferably againcharged with sulfur dioxid, as for cell 12, to make sure that all thecopper in the cathode -solution is in the cuprous condition. The drawingclearly shows the various methods of circulating the solution, asnecessity may arise, so that further verbal description will besuperfluous.

If it is found that the sulfur dioxid is not all taken up in thereducing tower 6, the excess may be piped, by means of pipe line 37, tothe bottom of the combining tower 2, where it may combine with theexcess of chlorin, liberated during electrolysis.

The solution issuing from the cathode compartment of electrolyzer 13,largely freed from its copper, overflows through pipe 13 and into tank14, from whence it is again'elevated and enters the anode compartment ofthe cell. Or if the diaphragm is permeable, the solution may be passedthrough it from the cathode to the anode compartment.

through the ore, by means of branch pipe 19, without going through thecombining tower 2. If it is desired to treat the ore for gold, thesolution is passed through the combining tower 2, but only in thepresence of chlorin. The sulfur dioxid may be temporarily shut 011".

The chlorin may be derived entirely from the electrolytic decompositionof the copper chlorid, as shown in cells 11, 12, and 13, or

it may partly be derived from the decomposition of salt in a separateapparatus, as shown at 24:. This represents an ordinary diaphragm cellfor the electrolytic decomposition of sodium chlorid, .into chlorin andcaustic soda.. The chlorin, by means of exhauster '25, and pipe line 23and 23, is forced into the combining tower 2, where it is absorbed bythe solution. The caustic soda (or carbonate) flows into tank 26, whereit comes in contact with a portion of the copper solution,'when byequation (14) the solution is purified by throwing out the baseelements, and again regenerating sodium chlorid. The purified solutionis then filtered from the precipitate and "again returned to thecircuit, by means of tank 28 and pump 29.

In depositing the copper in the electrolyzers'll, 12, and 13, it hasbeen found that when there is an excess of sulfur dioxid in thesolution, the deposited copper will not adhere to the catho es, butfalls to the bottom of the electrolyzers. To facilitate the gathering ofthe copper, and preventing of short circuits between the electrodes, thecells are constructed with a hopper bottom, in which the copperaccumulates. In the bottom of these hoppers, at the apex, are pipes 30,30", and 30, having valves and connecting with the main. 30, which leadsto a settling tank 27. The copper soon settles to the bottom, and leavesthe clear solution on top. This solution is then drawn off into tank 28and returned to the circuit. When sufficient copper has accumulated inthe copper settling tank 27, it is washed, removed, charged into afurnace, melted and cast intoingots, or'into anodes for electrolyticrefining, and for the separation of the copper from the precious metals.

The sulfur dioxid furnace is shown at 22,

'- and by means of the exhauster 31 and the pipe lines 32 and 32 thesulfur dioxid is- 1 copper iti's best not to attempt to get "thesolution below 0.5% or 10% copper. Much of this remainingcopper,afterissuingfrom the electrolyzers may be in the cuprous con-' dition.Before returningit to the ore it is desirable to first pass the solutionthrough the combining tower 2, in the presence of chlorin, so thatthe-cuprous chlorid still remaining in the solution will be convertedinto the cupric chloridi I The current which 'it is desirable to employ, 50 amperes pensqua're foot, makes it" impossible to combine, allof the chlorin released at the anode? with the sulfur dioxidin thesolution, during electrolysis.

' It is desirable, therefore, to-exhaustthe cxilorin from theelectrolyzers and force it in o the combining tower 2, where it-inaycome in contact with the excess of sulfur dioxid in the solution, orthe\excess from the reducingtower 6, or fresh sulfur dioxid from thegenerator 22. 4

The sulfur dioxid generator 22, may bea furnace, a sulfur burner, or anyother means of generating the gas.- Ordinarily. it will be a mufilefurnace, in which the ore is first roasted for its sulfur content, andthen charged into leaching .vats for the extraction of the coppr;- v

Cuprous chlorid is notsoluble in water. Neither is silver chlorid. If anattempt were made to convert the cupric chlorid into the cuprouschlorid, without the-presence of other chlorids, the cuprous chloridwould be precipitated. It is for this reason that a chlorid solutionisused, since both cuprous and silver chlorids'are soluble in chloridsolutions. A chlorid solution of sufiicient strength is, therefore, usedto retain the cuprous chlorid in solution.

i The slight and unessential modifications of the process and apparatusto treat other metals than those specifically mentioned will be evidentto any one skilled in the art, so that it will be useless and"unnecessary to give a detailed description foreach particular metal. IY

The granulationof the deposited copper appears to be affected-both bythe" current density employed and by the amount of sulfur dioxid in thesolution. By regulating these factors, any desired copper may beobtained. 'Having thus described granulation of the my invention,what 1. A process of extracting copperfiom its. A

ores which consists in treatingthe ore with an acid solution to dissolvethe copper; ap plying sulfur dioxid to the result ng copper solution inthel resence of some other chlorid to convert the dissolved-copper intothe cuprous chlorid; electrolyzing the resulting solution containing'thecuprous. chlorld, to

deposit the copper and liberate chlorin;

bringing the chlorin so liberated infcontact with the solution in thepresence of sulfur dioxid returning the regenerated acid solution to theore and repeating the cycle of solution, precipitation and.regeneration, as

before, until the copper in the ore is sufii-Y ciently extracted.

2. A process of extracting copper from its ores-which consists intreating the ore with an acid solution todissolve the copper; ap-

plying sulfur dioxid to the resulting copper solution in the presence ofa metal chlorid to convert the dissolved copper into the cuprouschlorid; electrolyzing the cuprous chlorid to deposit the copper andliberate chlorin; subdividing the solution; then" bringing the chlorin,liberated by the decomposition of the cuprous chlorid, in coni division,in the'presence of sulfur dioxid;

.t'act with the solution while in a state of subreturning theregenerated acid solution to the ore and repeating; the cycle, asbefore, until the copper in the ore is sufliciently extracted.

3. A process of extracting copper from its ores containing other metalswhich consists in treating the ore with an acid solutionto' dissolve thecopper and other metals applying'i sulfur .dioxid to the resultingcopper solution in the presence of other chlorids to convert thedissolved copper into cuprous chlorid electroly'zing the resultingsolution,

the chlorin so liberatedin contact with the solution in the presence ofsulfur dioxid; returning the regenerated acid solution to the ore andrepeating the cycle of solution,

precipitation and regeneration, as before,

until the copper and other metals in the ore are sufiicientlyextracted.

4. A process of extracting metals from their 'ores containing copperwhich consists in treating the ore with an acid solution to dissolve thecopper and other metals; applying sulfur dioxid to the solution in thewcontaining the cuprouschlorid', to deposit the copper and liberatechlorin; bringing presence of a metal chlorid; electrolyzing the cuprousand other metalchlorids to deposit the copper and other metals andliberate chlorin; subdividing the solution; then bringing the chlorin soliberated in contact with the solution in the presence of sulfur dioxid;returning the regenerated acid solution to the ore, and repeatingthecycle as before, until the metals in the ore are sufiicientlv extracted.

5. A process of extracting metals from their ores containing copperwhich consists in treating the ore with an acidsolution to dissolve thecopper and other metals; applying sulfur dioxid to the resulting coppersolution in the presence of other chlorids to convert the dissolvedcopper into cuprous chlorid; electrolyzing the resulting solution,containing the cuprous chlorid, to deposit the copper and liberatechlorin; bringing the chlorin so liberated in contact with water in thepresence of sulfur dioxid; applying the resulting acid solution to theore, and repeating the cycle, as before, until the-copper in the ore issufficiently extracted.

6. A process of extracting copper from ores which consists in treatingthe ore with an acid chlorid. solution to dissolve the copper; applyingsulfur dioxid to the resulting copper solution to convert the cupricchlorid into the cuprous chlorid; electrolyzing the resulting solution,containing the cuprous chlorid, to deposit the copper and liberatechlorin; bringing'the chlorin so liberated in contact with the solutionin the presence of sulfur dioxid; returning the regene-rated acidsolution to the ore, and re- I peating the cycle, as before, until thecopper in the ore is sufiiciently extracted.

7. A process of extracting copper from its ores which consists intreating the ore with an acid chlorid solution to dissolve the copper;applying sulfur dioxid to the resulting copper solution to convert thecupric chlorid into the cuprous chlorid; electrolyzing the cuprouschlorid to deposit the copper and liberate chlorin; subdividing thesolution; then bringing the chlorin so liberated, in contact with thesolution while in a state of subdivision, in the presence of sulfurdioxid; returning the regenerated acid solution to the ore and repeatingthe cycle, as before, until the copper in the ore is suflicientlyextracted. a

8. A process of extracting copper from its ores which consists intreating the ore with an acid chlorid solution to dissolve the cop per;electrolyzing the resulting copper chlorid, .first as the catholyte;then as the anolyte; bringing the chlorin released by the decompositionof the copper chlorid in contact with'the solution in the presence ofsulfur dioxid; returning the regenerated acid solution to the ore andrepeating the cycle, as before, until the copper in the ore issufficiently extracted. 4

9. A process of extracting copper from its ores which consists 1ntreating the ore with an acid solution to dissolve the copper; ap-

plying sulfur dioxid to' the resulting copper deposit the copper andliberate 'chlorin, first as the catholyte; then as the anolyte; bringingthe chlorin released by, the decomposition of the cuprous chlorid incontact with the solution in the presence of sulfur dioxid; returningthe regenerated acid solution to the ore and repeating the cycle, asbefore, until the copper in the ore is sufliciently extracted.

' 10. A process of extracting copper from its ores which consists intreating the ore ,with an acid chlorid solution to dissolve the copper;passing the chlorid solution-containing the copper through the negativecompartment of an electrolytic cell to deposit the copper andliberatechlorin; passing the so- 35 lution, after issuing from the negativecompartment, through the positive compartment; exhausting the chlorinreleased in the positive compartment and bringing it in contact with thesolutionin the presence of sulfur dioxid; returning the solution to theore and repeating the cycle, as before, until the copper in the ore issuhiciently extracted.

11. A process of extracting copper from its ores which consists intreating the ore 5 with an acid chlorid solution to dissolve the copper;applying sulfur dioxid to the solution to convert the cupric chloridinto the cuprous chlorid; passing the chlorid solution containing thecopper through the cath- 0 ode compartment of an electrolytic cell totact with the solution and sulfur dioxid while in a state ofsubdivision; returning'the regenerated acld solution to the ore andrepeating the cycle, as before, until the copper "in the ore issufficiently extracted.

12. A process of extracting copper from its ores containing other metalswhich con sists in treating the ore with an acid chlorid 5 solution todissolve the copper and other metals; applying sulfur dioxid to convertthe cupric chlorid into the cuprous chlorid; electrolyzing the solutioncontaining the cuprous chlorid and chlorids of the other ietals todeposit the metals and liberate chlorin; subdividing the solution;conduct-- ing the liberated chlorin and sulfur dioxid into the presenceof the subdivided solution; returning the regenerated acid solution tothe ore and repeating the cycle until the metals in the ore aresufficiently extracted.

13. A process of extractin copper from its ores containing gold whichconsists in, treating the ore with an acid chlorid solution to dissolvethe copper; electrolyzing the resulting copper chlorid solution todeposit the copper and liberate chlorin; bringing the chlorin, soliberated, in contact wit the solution in the presence of sulfur dioxid;applying chlorin in excess of that combining with the sulfur dioxid, tothe solution, to

dissolve the gold; returning the regenerated acid chlorid chlorinsolution to theore, and

repeating the cycle, as before, until thecop pew and gold in the ore aresuflicientlyextracted.

14. A process of extracting copper from its ores containing gold whichconsists in to dissolve the copper; electrolyzing the rel to'thesolution in excess of that combining.

treating theore with an acid chlorid solution sulting copper chlorid,solution to deposit the copper and liberate chlorin; bringing thechlorin so. liberated, in'contact with the solution in the presence ofsulfur dioxid; subdividing the-solution; applying chlorin with thesulfur dioxid to dissolve the gold;

- returning the regenerated acid solution, conper and gold taining anexcess of chlorin, to the ore, and repeatlng the cycle, as before,untilthe copin the ore are .sufiicientlyextracted.- r

15. A process of extracting. metals from their ores which consists intreating the ore with an acid chlorid solution to dissolvethemetals aschloride; electroly zing the result-- in extracting solution, containingthe metal chlorids, to deposit the metals and liberateChl0IlI1;-QXlll11SlIlg the chlorin so liberated,

from theelectrolyzen -and bringing it in contact with the solution inthe presence of sulfur dioxid; returning, the regenerated aci'dsolution-to the ore, and repeating the cycle, as before, until themetals in the oreare sufficientlyextracted."

16., A process of extracting metals from their ores which consists intreating the ore with an acid chlorid solution to dissolve the metals aschlorids;.electrolyzing the metal chlorids to deposit the metals andliberate chlorin; subdividing the solution; then bringing the liberatedchlorin in contact with the solution in the presence of sulfur dioxid;returning the regenerated acid solu- 'tion to the ore, and repeating thecycle, as

before, until the metals in the ore are sufiiciently extracted.

17. A process of'extractingcopper from its ores which consists intreating the ore with an acid solution to dissolve the copcplpper andliberate chlorin; bringing per; filtering the solution from the ore;subdividing the solution; applying sulfur di; oxid to the subdividedsolution in the presence of a metal chlorid to convert the dissolvedcopper into the cuprous chlorid; electrolyzing the cuprous chlorid todepositthe the orin so liberated in contact with the solution in thepresence of sulfur dioxid; returning the regenerated acid solution tothe ore and repeating the cycle, as before, until the copper in the oreis sufiiciently extracted. 18. A process of extracting copper. from itsores which consists in treating the ore with an acid solution todissolve the copper;

filtering the solution from the ore; subdividing the solution; applyingsulfur dioxid to the subdivided solution in the presence of a metalchlorid to convert the dissolved copperinto the cuprous conditionelectrolyzing thecuprous chlorid to deposit the copper and liberatechlorin; again subdividing the solution; and then bringing the chlorin,libcopper; applying sulfurdioxid to the solution to convert the cupricchlorid into the cuprous chlorid; maintaining sufficient sulfur dioxidin the solution to prevent the formation of cupric chlorid;electrolyzing the cuprous chlorid to deposit the copper and liberatechlorin; subdividing the solution; then bringing the excess of liberatedsov chlorin in contact with the subdivided solu tion to bring it toa hiher state of chlorination; returning the solution to the ore, and

repeating the cycle as often !as may be necessary until the copper inthe ore is suiiiciently extracted;

20. A process of extracting copper from its ores which consists intreating the ore with an acid chlorid solution to dissolve the'copper;subdividing the solution ina suitable reducing chamber;applying-sulfur dioxid to the subdivided solution to reduce the copperfrom the ciipric-to the cuprous 'condition;electrolyzing the cuprouschlorid to deposit the copper and liberate chlorin; subdividing theelectrolyzed solution; bringing the chlorin liberated duringelectrolysis, 1

in contact with the subdivided solution to bring it-to a higher state ofchlorination;

returning" the regenerated acid solution to the ore, and repeating thecycle, as before, until the copper in the ore is sufliciently extracted.

21. A process of extracting copper from its ores which consists intreating the ore with an acid chlorid solut-ion to dissolve the copper;subdividing the solution in a suitable reducing chamber; applying sulfurdioxid to the subdivided solution to reduce the cupric chlorid to thecuprous chlorid; electrolyzing the cuprous chlorid to depositthe copperand liberate chlorin; conducting the excess of sulfur dioxid from thereducing chamber to the combining chamber; conducting the electrolyzedsolution to the com bining chamber; subdividing the solution; conductingthe excess of liberated chlorin to the combining chamber where it comesin contact with the sulfur dioxid and subdivided solution; returning theregenerated acid solution to the ore, and repeating the cycle, asbefore, until the copper in the ore is suificiently extracted.

22. A process of extracting copper from its ores which consists inelectrolyzing the chlorid extracting solution to liberate chlorin anddeposit the metals; combining the chlorin so liberated with sulfurdioxid and Water to form acid, and then treating ores of copper with theacid solution so formed.

23. A-process of extracting copper from its ores which consists intreating the ore with an acid chlorid solution to dissolve the copper;converting the dissolved copper in the extracting solution into the formof cuprous chlorid, and then electrolyzing the resulting solution,containing the cuprous chlorid, in the presence of a substance capableof preventing the formation of cupric chlorid.

24. A process of extracting copper from its .ores which consists .intreating the ore with an acid solution to dissolve the copper;converting the dissolved copper in the, solution into the form ofcuprous chlorid and .then electrolyzing the resulting soltion containingthe copper in itschlorid combination in the presence of sulfur dioxidwhile maintaining sufiicient other chlorids in the solution to retainthe cuprous chlorid in solution.

25. A process of extracting copper from its ores which consists intreating the ore with a suitable solvent to extract the copper;converting the cupric chlorid in the solventinto the cuprous chlorid bybringing the solution in contact with sulfur dioxid; maintainingsufficient other metal chlorid in the solution to retain the cuprouschlorid in solution"; electrolyzing the cuprous chlorid solution toprecipitate the copper and regenerate the solvent, and then applying theregenerated solvent to the ore to extract more copper.

26. A process of extracting copper from its ores containing other metalswhich consists in treating the ore with an acid chlorid solution todissolve the copper and silver chlorid; applying sulfur dioxid to thesolution-to convert the cupric chlorid into the cuprous chlorid;electrolyzing the cuprous chlorid solution to deposit the copper;electrolyzing salt to generate chlorin and caustic soda; adding thechlorin to the solution-to dissolve the gold and other metals containedin the ore; and from time to time adding the caustic soda to thesolutionto purify it by precipitating out the base elements and regeneratingsalt.

27. A process of extracting metals from their ores which consists inelectrolyzing the metals in their chlorid-combinations to I deposit themetals and liberate chlorin, subdividing the solution afterelectrolysis, then bringing the liberated chlorin in contact with thesolution While in a state of s ubdivision, and then treating ores ofmetals With the solution so formed.

WILLIAM E. GREENAWALT.

lVitnesses:

JOHN G. MAY, GoRA M. GREENAWALT.

